The present invention is directed to gear manufacturing machines and more particularly to machines for cutting and grinding bevel gears.
In the production of gears, especially bevel gears, two types of processes are commonly employed, generating processes and non-generating processes.
Generating processes can be divided into two categories, face milling (intermittent indexing) and face hobbing (continuous indexing). In generating face milling processes, a rotating tool is fed into the workpiece to a predetermined depth. Once this depth is reached, the tool and workpiece are then rolled together in a predetermined relative rolling motion, known as the generating roll, as though the workpiece were rotating in mesh with a theoretical generating gear, the teeth of the theoretical generating gear being represented by the stock removing surfaces of the tool. The profile shape of the tooth is formed by relative motion of the tool and workpiece during the generating roll.
In generating face hobbing processes, the tool and workpiece rotate in a timed relationship and the tool is fed to depth thereby forming all tooth slots in a single plunge of the tool. After full depth is reached, the generating roll is commenced.
Non-generating processes, either intermittent indexing or continuous indexing, are those in which the profile shape of a tooth on a workpiece is produced directly from the profile shape on the tool. The tool is fed into the workpiece and the profile shape on the tool is imparted to the workpiece. While no generating roll is employed, the concept of a theoretical generating gear in the form of a theoretical xe2x80x9ccrown gearxe2x80x9d is applicable in non-generating processes. The crown gear is that theoretical gear whose tooth surfaces are complementary with the tooth surfaces of the workpiece in non-generating processes. Therefore, the cutting blades on the tool represent the teeth of the theoretical crown gear when forming the tooth surfaces on the non-generated workpiece.
Conventional mechanical gear generating machines for producing bevel gears comprise a work support mechanism and a cradle mechanism. During a generating process, the cradle carries a circular tool along a circular path about an axis known as the cradle axis. The cradle represents the body of the theoretical generating gear and the cradle axis corresponds to the axis of the theoretical generating gear. The tool represents one or more teeth on the generating gear. The work support orients a workpiece relative to the cradle and rotates it at a specified ratio to the cradle rotation. Traditionally, conventional mechanical cradle-style bevel gear generating machines are usually equipped with a series of linear and angular scales (i.e. settings) which assist the operator in accurately locating the various machine components in their proper positions.
It is common in many types of conventional mechanical cradle-style bevel gear generating machines to include an adjustable mechanism which enables tilting of the cutter spindle, and hence, the cutting tool axis, relative to the axis of the cradle (i.e. the cutter axis is not parallel to the cradle axis). Known as xe2x80x9ccutter tilt,xe2x80x9d the adjustment is usually utilized in order to match the cutting tool pressure angle to the pressure angle of the workpiece, and/or to position the cutting surfaces of the tool to appropriately represent the tooth surfaces of the theoretical generating gear. In some types of conventional mechanical cradle-style bevel gear generating machines without a cutter tilt mechanism, the effects of cutter tilt may be achieved by an altering of the relative rolling relationship between the cradle and workpiece. This altering is also known as xe2x80x9cmodified roll.xe2x80x9d
In the recent past, gear producing machines have been developed which reduce the number of machine settings necessary to orient a tool relative to a workpiece. These machines replace some or all of the settings and movements of the conventional mechanical cradle-style machine with a system of linear, rotational, and/or pivoting axes.
The present invention is generally directed to a machine for manufacturing bevel and hypoid gears including a column, a first spindle, and a second spindle. The column includes substantially vertical side walls including first and second areas. The first spindle is movably secured to the column at the first area and is rotatable about a first axis. The second spindle is movably secured to the column at the second area and is rotatable about a second axis. The first and second spindles are movable linearly with respect to one another in three directions. At least one of the first and second spindles is angularly movable relative to its respective area about a substantially vertical pivot axis.
In a preferred aspect, the present invention is directed to a machine for manufacturing bevel and hypoid gears including a column, a slide, a workpiece spindle, and a tool spindle. Vertical ways are located between a first vertical surface area of the column and the slide to allow movement of the slide along a first linear direction. First horizontal ways are located between the slide and the workpiece spindle to allow movement of the workpiece spindle along a second linear direction. Second horizontal ways are located between a second vertical surface area of the column and the tool spindle to allow movement of the tool spindle along a third linear direction. A pivot is connected to the tool spindle to allow movement of the tool spindle around a vertical pivot axis.